Benchmarks for surgical management of colorectal cancer were identified in a recent study. The study compared patient outcomes associated with synchronous and sequential colorectal and liver resections in patients with stage IV colorectal cancer. It was published in the Journal of Gastrointestinal Surgery (2015; 10.1007/s11605-015-2895-z).

In approximately 20% of cases, colorectal cancer has metastasized beyond the colon at the time of diagnosis. The liver is the most common site for these metastases. Although the approach to treating primary tumors within the colon and metastatic tumors in the liver continues to evolve, treatment typically involves chemotherapy plus surgical removal of both types of tumors. However, experts continue to debate whether surgical resection of primary tumors and metastatic tumors should be performed at the same time (synchronously) or in separate operations (sequentially).

The authors, all from the Mayo Clinic in Rochester, Minnesota, explained that the study results provide procedure-specific national benchmarks for postsurgical outcomes that will facilitate comparisons for quality improvement.

Analyzing data from patients within specific risk categories, the study also found that major complications after synchronous liver and colorectal resections vary and are related to the extent of liver resection performed and the type of colorectal surgery performed.

The risk for poor patient outcomes increases as the risk of each component surgical procedure increases. In other words, regardless of surgery timing, patients who require higher-risk procedures, such as a major liver resection due to the presence of larger or multiple metastatic tumors or high-risk colorectal resections, have poorer outcomes than those who underwent more minor surgery.

Synchronous resection of primary colorectal tumors and metastatic liver tumors is safe and effective in patients who require only minor liver resections.

“Our findings also show that performing preoperative risk assessments on patients who require both liver and colorectal resections could allow surgeons to more accurately predict patient outcomes and assist in preoperative planning and counseling these patients,” said lead author David Nagorney, MD, a general surgeon at Mayo Clinic.

In designing the study, the researchers used a large, multi-institutional database to identify a pool of 43,408 patients who underwent colorectal and liver resections for stage IV colorectal cancer. Before this study was conducted, only limited surgical outcomes data was available for these patients.

“Our primary aim was to establish the magnitude of risk that each component operation, both liver and colon, contributed to synchronous resections in order to determine which combination of colon and liver operations were most safe to be performed at the same time,” said Nagorney.

The researchers also reviewed the type or location of colorectal resection, whereas past studies only considered the extent of liver resection performed.

“We wanted to test the hypothesis that both the extent of the liver resection and the location or type of colorectal resection influence the overall risk and patient outcomes associated with these operations,” said the article’s first author, Christopher Shubert, MD, who is also a surgeon and Kern Scholar at Mayo Clinic.

The researchers assigned risk categories to each of the operations performed in the data pool, including colorectal and liver resections, and then compared 30-day postsurgical outcomes among patients within similar risk groups. They also compared outcome data between two groups of patients within each risk category: those who underwent synchronous colorectal and liver resections and those whose surgeries were performed sequentially.